“Is Christianity good for the world?” That’s the subject of an ongoing debate between renowned atheist Christopher Hitchens and a conservative and sometimes controversial Christian, Douglas Wilson.

What began as a correspondence between the two has led to a co-authored book, a debate tour, and now a fascinating documentary—a kind of behind the scenes look at that tour, featuring interviews with both men.

These interviews achieve a rare level of honesty and insight about what it takes to have faith in the modern world—or, conversely, what it takes not to have faith. The film shows the tremendous level of intellectual preparation that goes into the debates. And interestingly, even though Hitchens insists that no “thinking person” could believe the tenets of Christianity, the film also shows that he’s come to have a grudging respect for his devout opponent.

According to Hitchens, Douglas Wilson genuinely understands that Christians and secularists have some fundamentally different beliefs about morality because Christians believe that “the will of God is involved.”

The paradox is that even though Hitchens finds this a wrong and dangerous belief, he genuinely appreciates it when Christians are open about it and don’t try to blend in with the secularist crowd. He says Wilson is a “huge improvement” over other Christians that he’s known because Wilson really believes what he says, without hypocrisy or prevarication. “I know where I am with him” is how Hitchens puts it.

For his part, Wilson teases that Hitchens “would have made a very good Puritan.” He appreciates that Hitchens has some sort of innate sense about what’s right and wrong. But he keeps reminding Hitchens that he’s not appealing to any overarching standard of right and wrong when he talks about the subject, so this makes no sense. In fact, Wilson says that Hitchens is using the “coherent morality” developed by the Judeo-Christian worldview in order to criticize that very worldview.

For all their cooperation and good fellowship, Hitchens makes the stakes clear when he declares, “One of us not just has to lose the argument but has to admit real moral defeat. I think it should be him.”

The film takes its title from Wilson’s remark, “Basically a debate like this is more a collision of lives than it is an exchange of mere views.” Christians can learn a lot from watching this collision of lives. For one thing, we can learn about how to argue graciously while at the same time taking a strong, uncompromising stand for our beliefs. If an atheist as firm as Hitchens respects that kind of stand, that should tell us something.

The film ends on an intriguing note. Hitchens, who previously called the faith a “wicked cult,” admits that even if he had the power to “drive it out of the world,” he wouldn’t do it. Is this because he’s come to know one sincere, well-educated Christian? Or he grudgingly approves of the good works Christians do?

Collision doesn’t answer that question. But it does hint at what’s possible when such Christians know what they believe, and articulate their faith honestly and winsomely.